net: fix 64 bit counters on 32 bit arches

There is a small possibility that a reader gets incorrect values on 32
bit arches. SNMP applications could catch incorrect counters when a
32bit high part is changed by another stats consumer/provider.

One way to solve this is to add a rtnl_link_stats64 param to all
ndo_get_stats64() methods, and also add such a parameter to
dev_get_stats().

Rule is that we are not allowed to use dev->stats64 as a temporary
storage for 64bit stats, but a caller provided area (usually on stack)

Old drivers (only providing get_stats() method) need no changes.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/net/ixgbe/ixgbe_ethtool.c b/drivers/net/ixgbe/ixgbe_ethtool.c
index b35ef36741ef..da54b38bb480 100644
--- a/drivers/net/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ixgbe/ixgbe_ethtool.c
@@ -55,7 +55,7 @@ struct ixgbe_stats {
                                 offsetof(struct ixgbe_adapter, m)
 #define IXGBE_NETDEV_STAT(m)    NETDEV_STATS, \
                                 sizeof(((struct net_device *)0)->m), \
-                                offsetof(struct net_device, m)
+                                offsetof(struct net_device, m) - offsetof(struct net_device, stats)
 
 static struct ixgbe_stats ixgbe_gstrings_stats[] = {
         {"rx_packets", IXGBE_NETDEV_STAT(stats.rx_packets)},
@@ -998,16 +998,18 @@ static void ixgbe_get_ethtool_stats(struct net_device *netdev,
         struct ixgbe_adapter *adapter = netdev_priv(netdev);
         u64 *queue_stat;
         int stat_count = sizeof(struct ixgbe_queue_stats) / sizeof(u64);
+        struct rtnl_link_stats64 temp;
+        const struct rtnl_link_stats64 *net_stats;
         int j, k;
         int i;
         char *p = NULL;
 
         ixgbe_update_stats(adapter);
-        dev_get_stats(netdev);
+        net_stats = dev_get_stats(netdev, &temp);
         for (i = 0; i < IXGBE_GLOBAL_STATS_LEN; i++) {
                 switch (ixgbe_gstrings_stats[i].type) {
                 case NETDEV_STATS:
-                        p = (char *) netdev +
+                        p = (char *) net_stats +
                                         ixgbe_gstrings_stats[i].stat_offset;
                         break;
                 case IXGBE_STATS: